Total Station Survey

Introduction

One of the most recognizable instruments used by those in the geography field is a surveying station. The class was introduced to this instrument during our lecture meeting and was walked through how to use it. After all the formalities concluded the respective groups of the class went out and took survey points of campus mall at the University of Wisconsin-Eau Claire. Points were being measured for location (decimal degrees) and elevation.

Study Area

The study area was the campus mall of UWEC. A large open area in the center of UWEC, the campus mall has a gradual slope that makes taking elevation points and seeing elevation change quite easy. Our study area was 1 hectare of the campus mall.

Figure 1: The study area, Campus Mall at the University of Wisconsin-Eau Claire

Methods

The first step to any exercise is the setup. Setting up the Total Station may have taken the most time. The surveying part is arguably much more fun. The setup of the Total Station begins with the tripod. First, spread out the 3 legs to create a stable base. To create a stable base push the legs' stakes into the ground. The tripod is now ready. Next is to take the actual surveying tool and placing it on the tripod. To do this unscrew the guard of the tripod and screw in the Total Station. The knob that unscrews is found underneath the area that the Total Station will rest. Once the Total Station is securely screwed on; level the tripod. The level is a circle located on the Total Station. To level the tripod raise or lower the legs. There is a bubble located in the level and once this is steadied and centered in the middle of the circle the next step is to level the legs. There is another level located on the Total Station which resembles a standard level. This is leveled by turning 3 knobs located on the Total Station. Once this is leveled the Total Station is ready.

The next step was to setup a job. First, we had to turn on Bluetooth. Bluetooth is found under parameters in the menu. We ran into some trouble here because of the fact that we did not turn on the Bluetooth first. After setting up Bluetooth we moved onto the GMS. Here the job was created under TopSurv. The projection was set here (UTM Zone 15). After modifying the projection the Bluetooth manager appeared. Make sure that the Bluetooth is set to Total Station to get a match.

The most important aspect was to set a Backsight and an OCC point. To setup these go to the OCC/BS setup. The OCC point was collected earlier when setting up the Total Station. OCC1 is the point. Next, the backsight is collected. To collect the backsight we used the prism which is the instrument that locates the points. How the prism works is that the Total Station shoots a laser and the prism reflects the point back to the Total Station. The Total Station takes into account the height and time it took for return of the laser. The prism was set to 2 meters. To make sure we got accurate readings we entered the height of the Total Station. Once all the technical aspects are recorded hit HC set. The Total Station is ready to use.

The group rotated holding the prism and using the Total Station. To collect points use the GMS when on the point menu and hit measure. The Total Station has a cross hair in the lens which needs to be set on the prism. Once the point was measured we moved on and collected more. A total of 130 points were taken.

Results

Once all our points were collected they were transferred into Arc software. All of our points appeared on ArcMap and seemed to be accurate. Because of the recent change in the campus layout an updated basemap was not used. The large building that was once Davies Center is no longer there and has been replaced by campus mall.

Figure 2: The survey area including all survey points and OCC point. This is an outdated map as the large building where all the points lay no longer exists

We were asked to use kriging to show the change in elevation. Kriging was mentioned before in another blog but to refresh ourselves it uses points' z-values to create continous elevation estimates.

Figure 3: The survey area with Kriging visualization. This shows estimated continuous elevation from the points that were taken.

Figure 4: The 3D representation of Kriging. This shows the elevation change in an easier way to visualize. 

Discussion

There were a few kinks that were encountered but the group worked past them. Using a survey station is a highly accurate way to take elevation features. The area of campus mall was a optimal survey area because of its slight change in elevation. It was possible to see the change without having overwhelming elevations.

Conclusion

The high accuracy of the Total Station along with other factors make this surveying method highly regarded. Many surveyors use these tools because of the dependability.